Electromagnetic force strength training device

ABSTRACT

The present invention describes a system for utilizing electromagnetic force as resistance in a strength training device. A controller is used to receive desired exercise parameters from the user. Based upon the desired exercise parameters, an electric current level is calculated and applied to an impermanent magnet to generate an electromagnetic field. The electromagnetic field exerts an electromagnetic force on a magnet belonging to a force applicator to provide resistance to the user during the exercise of muscles with the force applicator. As a result, the strength training device provides resistance for the user in the form of an electromagnetic force rather than conventional gravitational force associated with free weights.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to strength training devices. More particularly, the present invention relates to using magnetic forces, rather than gravitational forces, for providing resistance during muscle training.

2. Description of the Related Art

The present invention relates generally to strength training devices. More particularly, the present invention relates to using magnetic forces, rather than gravitational forces, for providing resistance during strength training.

2. Description of the Related Art

Studies have shown benefits of muscle training include improved fitness, increase in muscle size, strength, power, and endurance, and increased bone density. Weight lifting, a form of resistance training, is an effective means of training muscle. In general, resistance training is the repetitive lifting of weights in order to overload and tear muscles of the human body. During a rest period after weight lifting, the torn muscle fibers are rebuilt by the body to be thicker so that they may withstand even higher stress loads. A typical session of weight lifting includes performing a few sets of a number of exercises, wherein each set includes lifting a given weight a number of times.

One popular form of resistance training uses free weights such as plate loading barbells or dumbbells. However, there are problems associated with using free weights. First, free weights are bulky and clutter weight room space. Free weights are generally made of a metal material, a rubber material, or both. Since the amount of metal and rubber material used for the dumbbell or plate is proportional to the desired weight, heavy dumbbells are large and cumbersome. Furthermore, in resistance training, the weight value lifted generally increases as the user progresses through the sets. This requires the user to use multiple sets of free weights during a given exercise. This leads to clutter in the weight room space, particularly if the free weights are not returned to their proper location.

Second, free weights offer very little in terms of workout customization. The user is limited to the increments available in the set of free weights. For example, a user wishing to increase the weight by one pound may be frustrated if the available set of weights increments in a five pound interval. The user is also limited to a given weight during the middle of a set. For example, the user may not decrease the weight value in the middle of a set without dropping and picking up a different set of free weights.

Third, free weights are inefficient since time is wasted changing weights between sets. In many gyms, there is only one unit of each weight increment due to space and cost considerations. If the desired set of weights is currently be used by another, this wait time may be even longer. Fourth, free weights pose safety concerns for both the weight lifter and those around him. For example, a weight lifter who loses control of the barbell places himself and those around him in danger.

Thus, there remains a need for an improved system and method of resistance training that addresses these problems.

SUMMARY OF THE INVENTION

Embodiments of the present invention include systems and methods for providing resistance to a user in the form of an electromagnetic force during the exercise of at least one group of muscles. In one embodiment, the present invention includes a strength training device comprising a force applicator for receiving a repetitious motion by the user during the exercise of at least one group of muscles, the force applicator including a magnet, an electromagnetic plate, wherein the electromagnetic plate generates an electromagnetic field based upon an electric current received, a user input indicative of a user's desired exercise parameters when performing the repetitious motion, and a controller for controlling the electric current applied to the electromagnetic plate, wherein the electric current applied is based at least in part upon the user input, and wherein the electromagnetic field exerts the electromagnetic force on the magnet, the electromagnetic force providing resistance to the user during the exercise of at least one group of muscles.

In another embodiment, the present invention includes a method for using electromagnetic force as resistance in a strength training device comprising receiving desired exercise parameters from a user, measuring the position of a force applicator used for repetitious motion by the user during the exercise of at least one group of muscles, wherein the force applicator includes a magnet, and calculating an electric current level based at least in part upon the desired exercise parameters and the position of the force applicator; and applying the electric current level to a wire wrapped around an impermanent magnet, the electric current level generating an electromagnetic field exerts an electromagnetic force on the magnet, the electromagnetic force providing resistance to the user during the exercise of at least one group of muscles

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and the advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a system diagram illustrating a system for resistance training in accordance with one embodiment of the present invention.

FIG. 2 illustrates a flow diagram of a method for converting a user's desired resistance value into an electric current level in accordance with one embodiment of the present invention.

FIG. 3 is a system diagram illustrating a system for resistance training in accordance with one embodiment of the present invention.

FIG. 4 illustrates an electromagnetic plate in accordance with one embodiment of the present invention.

FIG. 5 illustrates a variety of force applicators in accordance with one embodiment of the present invention.

FIG. 6 is a process flow diagram illustrating a method of providing resistance to a strength training device in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention.

The present invention is designed for use in strength training devices. As will be described with reference to the following figures, a variety of mechanisms are disclosed for utilizing electromagnetic force as resistance in a strength training device. More particularly, the present invention discloses an impermanent magnet exerting an electromagnetic field, the electromagnetic field exerting an electromagnetic force on a magnet belonging to a force applicator to provide resistance to the user during the exercise of muscles with the force applicator. The electromagnetic field may be controlled by adjusting the electric current applied to the impermanent magnet. Adjustments of the electric current are at least based upon the user's desired resistance along with properties of the impermanent magnet and the magnet within the force applicator. As a result, the strength training device provides resistance for the user in the form of an electromagnetic force rather than conventional gravitational force associated with free weights.

FIG. 1 is a system diagram illustrating a system for resistance training in accordance with one embodiment of the present invention. System 100 may be incorporated into a strength training device exercising muscles of the body. Exemplary exercises that may be performed with such a strength training device include press exercises, pulldown exercises, curl exercises, rowing exercises, and abdominal exercises. Depending upon the exercise, system 100 may include other components. For example, the press exercises such as the bench press or shoulder press require a bench or seat to assist in keeping the body of the user stationary when the muscles are being exercised. Similarly, a preacher curl exercise device includes a sloped bench to brace the elbows as the bicep muscles are exercised.

System 100 includes electromagnetic plate 120. An electromagnetic plate is an object that exerts an electromagnetic field in response to an electric current. The electromagnetic field may change orientation and strength based upon the direction and strength of the electric current received. In one embodiment, electromagnetic plate 120 remains in a fixed position during the use of strength training device 100. Depending upon the path of the repetitive motion, electromagnetic plate 120 may be positioned horizontally, vertically, or in various angles. In other embodiments, electromagnetic plate 120 may move during use of the strength training device in order to adjust the direction of the electromagnetic field. This may be desirable for exercises where the path of motion is not substantially linear.

Electromagnetic plate 120 includes impermanent magnet 121. An impermanent magnet enhances the magnetic field generated by a wire carrying an electric current. By wrapping the wire around the impermanent magnet, the electromagnetic field exerted by the electric current traveling through the wire may be enhanced hundreds or thousands of times. When current is not running through the wire, the impermanent magnet loses its memory of previous magnetizations. Examples of materials used in impermanent magnets include soft ferromagnetic materials such as soft iron and steel.

The electromagnetic field exerted from electromagnetic plate 120 interacts with force applicator 110. Force applicator 110 can be any physical structure for receiving a repetitious motion during the exercise of a muscle group. The physical structure of the force applicator is dependant on the exercise being performed. Examples of physical structures include a dumbbell used for curl exercises, a flat plate used for abdominal exercises, a pulldown bar used for back exercises, and barbells used for chest exercises. For example, in a bench press exercise, force applicator 110 is the barbell held by both hands and the repetitious motion is the barbell moving up and down in the vertical direction while the user is laying flat on a bench. In system 100, force applicator 110 moves vertically in the path illustrated by the dashed line.

Force applicator 110 includes magnet 111. Magnet 111 may be any material capable of producing a magnetic field. When an electromagnetic field is nearby magnet 111, the electromagnetic field exerts an electromagnetic force on magnet 111. This electromagnetic force provides resistance to the user during exercise with the force applicator. For example, the electromagnetic force may attract force applicator 110 towards electromagnetic plate 120, thereby providing resistance to the user as he lifts and lowers the force applicator along the path of the repetitive motion. In one embodiment, magnet 111 is a permanent magnet. Permanent magnets stay magnetized and produce a magnetic field capable of attracting or repelling other magnets. Examples of permanent magnets include magnets used to hold messages on refrigerator doors.

Electromagnetic plate 120 is coupled to controller 130 and power source 140 for controlling the electric current provided to the electromagnetic plate. Controller 130 receives desired exercise parameters as input from the user and calculates an electric current level as output. This electric current level is subsequently supplied to electromagnetic plate 120 by power source 140 to generate an electromagnetic field that exerts an electromagnetic force on force applicator 110, where the force exerted meets the desired exercise parameters. Examples of exercise parameters that may be received include the number of repetitions in a set, the resistance value for each repetition in the set, the range of motion for each repetition in the set, and the number of sets to be performed. In one embodiment, the resistance value may gradually decrease as the user approaches the desired number of repetitions. This allows the user to fully overload the muscles being exercised.

FIG. 2 illustrates a flow diagram of a method for converting a user's desired resistance value into an electric current level in accordance with one embodiment of the present invention. At step 210, the desired resistance value is converted into a gravitational force that the user associates with the desired resistance value when lifting free weights. At step 220, a calculation is performed to determine the strength and direction of an electromechanical field that is capable of exerting a force upon the magnet in force applicator 110 that is equivalent to the gravitational force. At step 230, the electromechanical field is used to determine the desired electric current. In one example, the desired electric current is calculated with the desired electromechanical field and properties of the impermanent magnet located within the electromagnetic plate.

Returning to FIG. 1, current is supplied to electromagnetic plate 120 at the desired electric current level by power source 140 once the desired electric current level has been calculated by controller 130. In response to the electric current, electromagnetic plate 120 exerts the desired electromagnetic field. The desired electromagnetic field in turn exerts an electromagnetic force upon the magnet 111 of force applicator 110, thereby simulation the direction and strength of the desired resistance value in the user input. The electric current is continually applied to electromagnetic plate 120 until the desired repetitions and sets have been performed by the user. Once the exercise parameters have been met, controller 130 signals power source 140 to discontinue applying electric current to electromagnetic plate 120. Without electric current, electromagnetic plate 120 no longer exerts an electromagnetic field and the electromagnetic force felt by force applicator 110 disappears.

In one embodiment, an activation sensor is included in force applicator 310 to allow the user to activate and deactivate the electric current flow to electromagnetic plate 120. Thus, a user may deactivate the electromagnetic force when the desired numbers of repetitions and sets have been successfully performed. The activation sensor also delays the exertion of the electromagnetic force on force applicator 110 until the user is ready to begin the set. In one example, the activation sensor is based upon the user's grip of force applicator 110. Thus, if a use loses his grip on the force applicator, the electromagnetic force will automatically deactivate. This may serve as a safety precaution for when the user is fatigued or injured during the set. The activation sensor may communicate with controller 130 through a variety of communication techniques including wireless and wired technologies.

FIG. 3 is a system diagram illustrating a system for resistance training in accordance with one embodiment of the present invention. Similar to system 100 of FIG. 1, system 300 provides resistance, in the form of electromagnetic force, for a user exercising with force applicator 310 by controlling an electromagnetic field exerted from electromagnetic plate 120. Controller 130 controls the electromagnetic field by adjusting the electric current applied to electromagnetic plate 120. System 300 further includes sensor 350 coupled to controller 130. Sensor 350 measures positional information of components in system 300 for controller 130. This positional information may be used in determining whether electromagnetic force should be exerted on the force applicator or calculating the desired electric current level. It is generally known that the strength of the electromagnetic force weakens with distance. Thus, by measuring the distance between the source of the electromagnetic field and magnet 311, controller 130 may more accurately calculate the electromagnetic force exerted on force applicator 310. Examples of positional information that may be measured by sensor 350 include the absolute position of force applicator 310, the absolute position of electromagnetic plate 120, and the displacement distance between force applicator 310 and electromagnetic plate 120. Depending upon the positional information being measured, the location of sensor 350 may change. In some instances, sensor 350 may even be located within a component of system 300. For example, sensor 350 may be located within electromagnetic plate 120. It is to be understood by those skilled in the art that system 300 may include multiple sensors depending upon the positional information being measured. For example, if three-dimensional positional information is being measured, system 300 may include at least one sensor for each dimension.

In this embodiment, sensor 350 is located parallel to the path of motion of force applicator 310. The sensor determines the distance between force applicator 310 and electromagnetic plate 120 by communicating with identification 312. Since force applicator 310 is in motion when system 300 is in use, it is desirable for identification 312 and sensor 350 to communicate via wireless technologies such as infrared, wireless, or Bluetooth to avoid entanglement issues associated with wired communications. However, wired technologies are also acceptable. Identification 312 may also provide information besides positional information to sensor 350. In one embodiment, identification 312 may be used by controller 312 to look up the properties of the magnetic field of magnet 311 within force applicator 310. Alternatively, sensor 350 may read the magnetic properties directly from identification 312. The properties of the magnetic field are helpful in the calculations of the electric current level that should be applied to exert the desired electromechanical force on the force applicator. This may be particularly useful in resistance training systems that incorporate multiple force applicators. For example, a multi-purpose resistance training system that includes exercises using both dumbbells and barbells may be associated with multiple force applicators. Thus, it is important for controller 130 to know the properties of the force applicator currently in use.

In one embodiment, sensor 350 tracks the displacement distance between force applicator 310 and electromagnetic plate 120 by continuously measuring the position of force applicator 310. Changes in the displacement distance may have a direct effect on the electromagnetic force exerted upon force applicator 310 since electromagnetic force weakens with increased distance. Thus, to compensate for changes in electromagnetic force as the force applicator travels the path of the repetitive motion, controller 130 may dynamically adjust the electric current applied to electromagnetic plate 120 to account for changes in the position of the force applicator 310 with respect to the electromagnetic plate 120. In one example, the electric current is dynamically adjusted to maintain the electromagnetic force associated with the desired resistance value. This allows the user to feel a constant force that resembles traditional free weights as the distance between electromagnetic plate 120 and force applicator 310 changes during the path of motion of the exercise.

Tracking (i.e. continuously measuring) the position of force applicator 310 also offers many other advantages. For example, tracking the position of the force applicator helps controller 130 determine when a repetition has been successfully performed. Tracking the position of force applicator 310 also allows controller 130 to set working boundary 360. Working boundaries define zones where the user desires electromagnetic force to be exerted on force applicator 310. When force applicator 310 is within the working boundary 360, controller 130 calculates the desired electric current level and power source 140 applies the desired electric current level to electromagnetic plate 120. When the force applicator is outside working boundary 360, electric current is not applied to electromagnetic plate 120. Since electromagnetic force is present only within the working boundaries, this allows a user to lift force applicator 310 with ease and get into the proper position for the exercise before experiencing resistance on the force applicator, thus avoiding fatigue before the beginning of the exercise. This feature also improves the safety of resistance training by deactivating the electromagnetic field when the user loses control of the force applicator. In traditional resistance training using free weights, a user who can no longer complete the repetition due to fatigue or injury will lose control of the free weight, resulting in injury to the user or those around him. By limiting the working boundary to the path of the repetitive motion, any loss of control by the user will likely deviate from the expected path, thereby deactivating the electromagnetic force and protecting the user. Since there may be small fluctuations that may occur between repetitions, the working boundary may be expanded slightly to address this issue. In one example, the working boundary 360 may be set by tracking the motion of the first repetition and setting the working boundary to the path of that motion. In other examples, the working boundary is set by the user as user input.

In one embodiment, a working boundary may also be broken down into multiple sub-working boundaries where each sub-working boundary is associated with a resistance value and a range of motion. The sub-working boundaries may be overlapping or non-overlapping. This allows for more detailed customization of the exercise program. For example, a user wishing to target specific portions of the repetitive motion may increase or decrease the resistance in sub-working boundaries that correspond to these specific portions.

FIG. 4 illustrates an electromagnetic plate in accordance with one embodiment of the present invention. Electromagnetic plate 410 includes impermanent magnets 411 to 414. Depending upon the desired electromagnetic field, electromagnetic plate 410 may include fewer or more impermanent magnets. In one embodiment, the number of impermanent magnets within the electromagnetic plate is dependant on the working boundary. For example, a resistance training device that performs exercises within a four feet by four feet square may have impermanent magnets placed in a grid formation covering the square area. The impermanent magnets are connected in series by a wire for carrying electric current. It is desirable for the wire to be wrapped around each impermanent magnet in a uniform manner so that each magnet exerts a consistent electromagnetic field when electric current is applied.

FIG. 5 illustrates a variety of force applicators in accordance with one embodiment of the present invention. Force applicators 510, 520, and 530 may be used interchangeably in a resistance training system 300 of FIG. 3. Alternatively, a single force applicator may be used in resistance training system 100 of FIG. 1. Force applicator 510 illustrates a pair of dumbbells. Each dumbbell includes a handle 111 that has a magnet. In one embodiment, the magnet is a permanent magnet. Each handle 111 is attached to end plates 512. The end plates may be made from any non-magnetic material. In one example, the end plates are made of rubber for its high durability and wear. While the end plates are not a required in generating the electromagnetic force, they do serve an aesthetic function in that the force applicator resembles a traditional dumbbell. The end plates may also serve a practical purpose by housing other components such as identification 312 of FIG. 3.

Force applicator 520 illustrates a barbell. The barbell includes handle 521 and end plates 522. In contrast with force applicator 510, handle 521 is made of a non-magnetic material while end plates 522 include magnets. Other configurations where the handle is a magnet and the end plates are magnets or where both the handle and end plates are magnets are also acceptable. Force applicator 530 illustrates a pulldown bar. The pulldown bar is made of a non-magnetic material. The pulldown includes magnet 531 housed within force applicator 530. Advantages to housing the magnet within another material include protecting the magnet from the damage during use of the force applicator.

FIG. 6 is a process flow diagram illustrating a method of providing resistance to a strength training device in accordance with one embodiment of the present invention. Process flow diagram 600 begins with the resistance training device in a standby mode. The controller remains in standby mode until it receives the user's desired resistance parameters at step 610. At step 620, the controller performs device checks to determine whether the device is ready. This may include determining the current position of the force applicator and the status of an activation sensor. At decision 630, the controller determines whether the device is ready. If the device is not ready, the electric current is deactivated at step 670 and the device checks in step 620 are repeatedly performed until the device is ready. When the device is ready, the desired electric current level is calculated at step 640 and applied to the electromagnetic plate at step 650. In one embodiment, the desired electric current level is calculated by taking into consideration the position of the force applicator, the properties of the magnet within the force applicator, and the properties of the impermanent magnet or magnets within the electromagnetic plate. At decision 660, the controller determines whether there are more repetitions. For example, more repetitions may be required if the target number of repetitions provided in the user's desired resistance parameters has not been reached. If there are more repetitions to be performed the device checks of step 620 are performed. On the other hand, if there are no more repetitions to be performed, the electric current is deactivated and the flow diagram comes to an end.

The controller of the present invention may generally be implemented on any suitable computer system (e.g., microprocessor). In addition, the present invention may be implemented as computer-readable instructions stored on any suitable computer-readable media.

Although illustrative embodiments and applications of this invention are shown and described herein, many variations and modifications are possible which remain within the concept, scope, and spirit of the invention, and these variations would become clear to those of ordinary skill in the art after perusal of this application. For instance, although the specification has described method of dynamically adjusting the motor resistance value stored within the motor controller, other parameters may also be dynamically adjusted. Moreover, the present invention may be used in a system employing a various types of motors. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims. 

1. A strength training device arranged for providing resistance to a user in the form of an electromagnetic force during the exercise of at least one group of muscles, the strength training device comprising: a force applicator for receiving a repetitious motion by the user during the exercise of at least one group of muscles, the force applicator including a magnet; an electromagnetic plate, wherein the electromagnetic plate generates an electromagnetic field based upon an electric current received; a user input indicative of a user's desired exercise parameters when performing the repetitious motion; and a controller for controlling the electric current applied to the electromagnetic plate, wherein the electric current applied is based at least in part upon the user input, wherein the electromagnetic field exerts the electromagnetic force on the magnet, the electromagnetic force providing resistance to the user during the exercise of at least one group of muscles.
 2. The strength training device as recited in claim 1 wherein the repetitious motion is perpendicular to the direction of the electromagnetic field.
 3. The strength training device as recited in claim 1 wherein the electromagnetic plate includes a wire wrapped around at least one impermanent magnet, wherein the electromagnetic field is generated when electric current is carried through the wire.
 4. The strength training device as recited in claim 1 further comprising at least one sensor for measuring positional information
 5. The strength training device as recited in claim 4 wherein the positional information is used by the controller to calculate the electric current to apply to the electromagnetic plate.
 6. The strength training device as recited in claim 5 wherein the positional information includes the distance between the force applicator and the electromagnetic plate.
 7. The strength training device as recited in claim 4 wherein the positional information is continuously measured.
 8. The strength training device as recited in claim 7 wherein the positional information is used by the controller to determine whether the force applicator is within a working boundary.
 9. The strength training device as recited in claim 8 wherein when the force applicator is outside the working boundary, current is not applied to the electromagnetic plate.
 10. The strength training device as recited in claim 9 wherein the working boundary is set based upon the path of the repetitive motion.
 11. The strength training device as recited in claim 7 wherein the controller dynamically adjusts the current applied to the electromagnetic plate according to the position of the force applicator with respect to the electromagnetic plate.
 12. The strength training device as recited in claim 4 wherein the user input includes a desired resistance value associated with a range of motion that is part of the repetitious motion and the current applied to the electromagnetic plate is dynamically adjusted to maintain the desired resistance value throughout the range of motion.
 13. The strength training device as recited in claim 1 wherein the user input includes a desired number of repetitions and the electromagnetic force gradually decreases as the user approaches the desired number of repetitions.
 14. The strength training device as recited in claim 14 wherein the force applicator further includes an activation sensor, wherein electric current is applied to the electromagnet plate based upon the state of the activation sensor.
 15. A method for using electromagnetic force as resistance in a strength training device comprising: receiving desired exercise parameters from a user; measuring the position of a force applicator used for repetitious motion by the user during the exercise of at least one group of muscles, wherein the force applicator includes a magnet; and calculating an electric current level based at least in part upon the desired exercise parameters and the position of the force applicator; and applying the electric current level to a wire wrapped around an impermanent magnet, the electric current level generating an electromagnetic field exerts an electromagnetic force on the magnet, the electromagnetic force providing resistance to the user during the exercise of at least one group of muscles.
 16. The method as recited in claim 15 wherein when the position of the force applicator is outside a working boundary, the electric current level is zero.
 17. The method as recited in claim 15 wherein the electric current level is further based upon the position of the force applicator with respect to the electromagnetic plate.
 18. The method as recited in claim 15 wherein the desired exercise parameters include a desired resistance level associated with a range of motion that is part of the repetitious motion.
 19. The method as recited in claim 18 wherein the electric current level is dynamically adjusted to maintain the desired resistance level throughout the range of motion.
 20. The method as recited in claim 15 further comprising determining the state of an activation sensor belonging to the force applicator, wherein electric current is applied to the electromagnet plate based upon the state of the activation sensor. 